Flash flotation of free coarse gold using dithiophosphate and dithiocarbamate as a replacement for traditional amalgamation

Abstract

This article develops the flash flotation as an alternative method to gravitational separation and amalgamation in order to achieve a greater recovery of coarse native gold through selective hydrophobicity. This method is directly applicated in the discharge of the mills and / or classifiers to recover free and coarse gold; which size is superior than approximately 150 micrometers. Physicochemical characterization of the free gold surfaces was carried out by the measurements of contact angle, Z potential (ZPC) and atomic force microscopy (AFM). The reagent was determined by specific conditions (basic pH, no requirements of an activator and a flotation time of the order of 2 minutes) achieving a superior recovery than 90%. In this case, the isoamyl dialkyl dithiophosphate collector (AERO 3501®) was the reagent which basically got the best results.